Power relay



March 1939- 0.13. GRANDSTAFF 2,152,042

POWER RELAY Filed Feb. 6, 195'? 2 Sheets-Sheet 1 INVENI'ORZ FIG. 0THO.0. GRAND'STAFF BY fig, 3

,ATTORNEYS.

March'28, 1939. O, GRAN'DsTAFF 2,152,042

POWER RELAY 2 Sheets-Sheet 2 Filed Feb. 6, 1937 85 33 I I 90 85d? 5 5 5FIG; H

mm OTHO D. GRANDSTAFF V v ATTORNEYS.

Patented Mar. 1939 POWER RELAY.

OthoD. Grandstaff, Chicago, 111., aseignor to Associated ElectricLaboratories, Inc., Chicago, Iil., a corporation of Delaware ApplicationFebruary 0, 1931, Serial rim 124,420

1 Claim. (01. zoo-s1) This invention relates to improvements in powerrelays intended primarily for use on alternating current circuits andadapted for the remote control of various line circuits and the likewhere it is desired to make and break circuits having currents ofconsiderable magnitude passing therethrough.. The power relay of thepresent invention 'is of the magnetic type and l is capable of beingoperated by either direct or alternating current for the purpose ofclosing circuits, such as the circuits to battery'chargers and batteryeliminators or the like, although it may have other uses.

The principal object of the invention is to provide an improved magneticrelay of simple,

compact construction which may be manufactured with ease and economy andwhich will be eiiiclent in use. A further object of the invention is toprovide an improved relay comprising improved means for mounting themagnetizable core and thearmature which is actuated when the'core isenergized. Another object is to provide a magnetic relay having a coreand an armature in combination with means for rel lating the magneticfield which must be applied to the armature to actuate it. Still anotherobject of the invention is to provide an improved power nelay havingimproved meansfor controlling the intensity and time relation of themagnetic fleld in different parts of the core for the purpose ofpermitting the device to he employed emciently in an alternating currentcircuit- A further object of the invention is to' provide an improvedpower relay having means for effecting an abruptshut-oif of the arewhich normally tends to continue when a circuit is broken. Other objectsrelate to various features of construction and arrangement which willappear more fullyhereinaiter. The nature of the invention will beunderstood from the following specification taken .with the accompanyingdrawings in which .two embodi ments of the invention are illustrated.Inthe drawings, Figure 1 shows a rear elevation of one form of powerrelay embodying the present invention; Fig. 2 shows a front elevation ofthe relay illustrated inFlg, l; ,7 Fig. 3 shows abottom plan view of therelay 5 illustrated in Figs. 1 and 2;

Fig. 4 shows a side elevation of the relay illustrated in Figs. 1 and 2,looking toward the left asvlewedinFig.1;

a Fig. 5 is a somewhat tic view. of the circuit connections of a powerrelay embodying the present invention, showing one useto which the relaymay be put;

Fig. 6 is a perspective view of the magnetic core and magnetizing coilof the relay shown,

in Figs. 1 to 4, inclusive, with a portion of the 5 bracket by which thearmature is supported on I the upper portion of the core broken away; I

Fig. '1 is a perspective view of the armature which is actuated by thecore illustrated in Fig. 6; together with the spring contacts which are10 operated by the movement of the armature: I

Fig. 8 shows a top plan view of the shaft and swing by which themovement of the armature is controlled;

Fig. 9 shows a side elevation of the lever arm l5 laminations of ashading coil employed 'in the pole face as shown in Fig. 6; and

Fig. 11 is a bottom plan view of a modiii form of the invention in whichmagnetic blowout coils are employed for preventing arcing of thecontacts when the circuit is broken. y

Before proceeding toa description of the con- 25 struction of theimproved power relay, reference will be made to the circuit connectionsof one possible use of the invention, as illustrated in Fig. 5; As thereshown, two line conductors I5, leading from a source of alternating ordirect current supply, are connected immovable con-' tact members it,each of which is adapted to engage either one of two stationary'contactsII and It. The contacts I! are connected by con ductors it to theterminals of a' load 21, and as the contacts ll areconnected. byconductors 22 to the terminals of another load 23. By changing thepositions of the movable contact members I, either of the loads II or 23maybe connected in the circuit of the line conductors ll. 40

This movement'of the contact members I. is effected by'a magnetizablearmature 24 which is' adapted to be actuated by a magnetisable core ll.The winding of the core Ilia adapted to be energized by a current.supplied theretos throughoonductors 2t,'leading from the ree ondarywinding of a transformer 21 which has j its. primary windingconnectedthrough conductors II with a suitablealternating currentsupply. Aswitch-Ilisconnectedinoneottheeonducton so It which,- forexample, may be associated with the line conductors of atelephonecircuit, the switch 2! being located at'a point remote from'thelocsticn'o'f'therelaywhmhcontrchthecontea-imam".

As shown in Figs. 1, 2, 3, 4, and 6, the magnetizable core of the relayis an E-shaped member, made up of superimposed iron laminations, securedtogether by rivets 25a, the core comprising parallel outer arms 25b anda central arm 25c upon which the magnetizing coil is positioned. Thesearms 25b and 250 have pole faces 26d and Ne, respectively, the centralarm 250 being adapted to be engaged by the armature 24 when the coil 30is energized. The anns 25!) are preferably slightly shorter than the armlie so that the central arm is the only one actually engaged by thearmature, there being small air gaps between the pole faces 25d and thearmature, an arrangementwhich is adapted to prevent chattering when therelay is in use. The coil 80 is provided with an insulating covering 30aand is wound on an insulating spool having heads "b at its ends, thelength of the coil being such that the central arm 250 of the coreprojects beyond the adjacent insulating head 30b of the spool, as shownparticularly in Fig. 1. This pro- Jecting portion of the arm 25c of thecore is provided with a pair of parallel slots ing inwardly from thepole face He thereof, as shown in Fig. 6, and these slots are occupiedby portions of the shading coils 3i which are shown as being made up ofsuperimposed laminations lla of copper or the like, thus formingcontinuous rings which surround the outer end portions of the centralarm 28c of the core. These shading coils, due to curents induced thereinby the magnetic flux, are adapted to produce magnetic fields opposed tothose caused by the winding 80 in the outer 250 of the core, thuscausing the resultant magnetic flux in the outer portions of the centralarm to be out of phase with the magnetic flux passing through theportion of the pole face which lies between the two shading coils, withthe result that a continuous magnetization is maintained in some portionof the pole face when the coil 80 is energized by alternating current,so that the armature 24 will be attracted to the core as long as thecurrent continues to pass through the coil 30. The laminations lid ofeach shading coil may be secured together and the apertures lib of theshading coils are adapted to be fitted closely by the projectingportions of the magnetic core so that the shading coils are thereby heldfirmly in position.

The core 2! is connected with a parallel in- Iulating plate 83, of"Bakelite" or other suitable material, which is attached to the core atthe lower end of the relay by an internally threaded sleeve 34, engagedat one end by a screw ll Pissing through the insulating plate and at theother end by the threaded extremity of one of a series of studs 8! whichpass through the core. At the upper end of the core II, the side arms25b are connected with the insulating plate II by a metal bracket 31,which has the form shown particularly in Figs. 4 and 6. This bracketcomprises a top plate I'Ic having depending therefrom a pair of-iianges31b which are secured to the insulating plate a by screws ll engagingthreaded apertures therein. The depending flanges 31b of the bracket areformed in rally with parallel ransversely extending arms 31c, which havetheir extremities turned inwardly, as shown at lhL'to seat against thefaces of the upper ends of the arms Ilb oi the cores These lnturnedextremities IId are provided with threaded apertures which are engagedby the threaded portions of two of the studs ll previously referred to.

25 extend-- portions of the central arm which the armature is carried.The

The bracket 3! which thus connects the insulating plate 33 with theupper end of the core, also serves to support the armature 2- which, asshown in Figs. 4 and 7, is made up of a plurality of laminations 24a ofmagnetizable material having a metal plate 24b seated against the outerside thereof. A hinge bracket 40 seats against the inner edge of thestack of laminations 24a and this bracket is secured to the laminationsand to the plate 24b by rivets 4|. of the hinge bracket, there ispositioned an insulating block 42 upon which are seated the movablecontact members ii which are in the form of flat leaf springs of bronzeor the like, each carrying a pair of oppositely projecting contact lugsI So and I6?) at its lower extremity. The contact springs l8 divergedownwardly from each other and their upper ends are engaged on theirouter sides by an insulating plate 43 on which is seated a metal plate44. A pair of screws 45 extend through the plate 24b, through thelaminations of the armature, through the bracket 40, through theinsulating members 42 and 43, the upper ends of the spring contact armsl6 and through the plate 44 which has threaded apertures to receive theends of the screws, as shown in Fig. 7, so that the upper ends of thecontact springs II are mounted rigidly on the armature and are insulatedtherefrom.

The arms 40a of the bracket 48 extend on the inner sides of the arms 81cof the bracket 3! and are pivotally connected therewith by a shaft 41which extends through aligning apertures in the ends of the arms 40a andin the adjacent portions of the arms 31c. This shaft 41 has woundthereon a coil spring 48, shown more particularly in Fig. 8, which hasits middle part engaging apertures in the shaft and which has itsopposite end portions wound in opposite directions in helical fashionabout the shaft, the extremities of the spring terminating in arms 48awhich are provided with transversely bent extremities 48b arranged tofit into apertures 40b, formed in the arms 40:: oi the bracket 40 byshaft 41 is normally held against rotation and the spring 48 tendsnormally to move the armature 24 to its open or retracted position, asshown in Fig. 4. The extent of this opening movement may be limited bythe engagement of the upper side 'of the armature with the edge of thetop plate 31a of the bracket II, but it may also be limited by theengagement of the contact lugs Ito with the stationary contacts ashereinafter more fully described. In order that the tension of thespring 48 may beadjusted to regulate, the force which must be applied toovercome the spring when the armature is attracted to its core, meansare provided for turning the shaft 41 in its bearings. For this purpose,one end of the shaft isconnectedtoacrankarmflwhichisintheformofaflatplateadaptedtoseatagainst one of the side arms 31c of thebracket 81. This crank arm 4| has an aperture 40a in one end thereofwhich is provided .with outwardly extending notches 40b, shown in Fig.9, into which a portion of the metal of theshaft 41 enters when the endof the shaft is riveted over the face ofthe crankarm asshownin Fig. 8.This crank am my be used for turning the shaft 41 to create the. desiredtension in the spring 4| and. when that has been accomplished, the arm40 may be secured in adjusted screw II which engages an aperture in theouter end of the arm and a threaded aperture in the Between the arms 40aparts of the armature moves from adjacent arm 310 of the supportingbracket. By this method of construction the armature 24 is causedto'move about a pivotal axis which excaused to beexerted on the armatureby the several pole faces.

The large cylindrical heads 33a of the studsv 39 are adapted to seatagainst an upright support or panel 5| of an instrument board or thelike, and the relay is adapted to be secured to this panel by screws 52which pass through the panel and engage the internally threaded sockets39b of the heads 36a, the screws being inserted thus mounted on the in'plate 33 to from the rear side of the panel. The heads 38aof the studsare provided with transverse slots 360 for engagement with a screwdriver or the like during the operation'of securing the insulatthe coreof the relay. Although the relay may be mounted in various positions, itmay preferably be located in an upright position such as that shown inFig. 4, with the springs l6 extending substantially in 'a vertical planeso that dust will not collect materially on the operating surfaces ofthe contacts. when 7 panel 5|, theinsulating plate 33 is at the'front ofthe assembly in a convenient position for connecting to the contactscarried there by the various conductors of the circuit inwhieh the relayis used, such as the conductors which have-been shown by way of examplein Fig. 5.

; pair are secured together by screws 51 and also is provided For thepurpose of connecting the conductors 26 to the terminals of the coil 39by which the magnetizable core at its upper end with a pair of metalliccontact plates 54 and these are opposed on the inner side of the plateby metal terminal plates 55 to which the conductors 56 leading from theterminals of the coil 30 are soldered or otherwise secured. The plates54 and I! of each by contact screws 58 by which the ends of theconductors 25 may be clamped against the faces of r the plate 54 tocomplete the electrical connections.

The line conductors llshown in Fig. 5 are adapted to be connected tocontact plates 39 which are located on the face of the insulating plate33 opposite other metal plates 3| which are located on the inner surfaceof the insulating plate. These terminal plates ii are soldered orotherwise secured to conductors 92 which have their other ends solderedor otherwise at.- tached to the contact springs l3, adjacent the freeends thereof. The plates 99 and 3| of each' pair are secured togetherand .to the plate 33 by screws 93 and also by contacf screws 34 whichare adapted to receive beneath their heads the,

extremities of the conductors ll. The contacts l3,shown in Fig. 5, areriveted or otherwise secured to the free ends of metal brackets 33 whichhave the-angular form shown particularly in Fig. 3, each bracket havinga portion Ila seated against the inner face of'the plate 3 3 andconnected by anoutwardly inclined portion 9th with an extremity 95cwhich lies parallel .to the portion a and to which the contact i9 isriveted or otherwise secured.

contact plate 33 is located on the outer face 6} proportions of theparts, substantially equal forces of attraction may be is energized, theplate 33 may be used with the magnetizing coil 3 a opposite the portionat plates 99 are sethe insulating plate of .each bracket 83 and theseshown in Fig. 5' are carried by brackets 19 which have their inner ends19a seated against the inner face of the plate, 33 and which haveinclined portions 10b connecting the portion Ila with the extremities10c upon which the concured to the portion 95 and to the plate 33by acontact screw 69 which tacts I9 are mounted in positions offset from theplate 33 and from the portions 65a of the bracket 65. Contact plates IIare seated on the outer face of the plate 33 opposite the inner portions19a of the brackets 19 and these parts are secured together and to theinsulating plate 33 by screws 12 and also by contact screws 13, whichclamp the ends of the conductors 22 in position, thus connecting thecontacts IS with the load 23, as shown in Fig. 5. By this method ofconstruction, the terminal screws by which all of the conductors areconnected to the relay are readily accessible on the front facepf theinsulating plate 33 while all of the movable parts of the device areconcealed behin this plate. v, When the relay as thus constructed isconnected in the circuit in the manner illustrated in Fig. 5, theclosing of the switch 29 will energize the electromagnet so that thecore 25 will attract the armature from the position shown in Fig. 4,thereby causing the movable contact springsv It to be swung to aposition wherein the {contact lugs IGb carried by their extremities willengage the 'pontacts i9 and thus connect the line conductors IS with theload 23. While the winding 30 of the core 23 is thus energized, theshading coils 3| will cause a lag of the magnetic field in certain partsof the pole face of the core behind the field in another part so thatthere-will be a continuous attraction of the armature 24 over some partof its area during the entire time that the coil 39 is energized. Whenthe switch 29 is opened, the spring 49 will at once cause the armature24 to rise to the position shown in Fig. 4, and during this movement thecontact lugs lIa carried by the contact springs I will move intoengagement with the contacts l8, thus connecting the conductors ll withthe load 2|. The mounting of the contact springs i9 is such that as itscontact lugs engage or disengage either set of contacts II or l9, therewill be a wiping contact of the surfaces of the metalso that a goodelectrical connection isestablished each time that a contact is made.Although the extreme upper movement of the armature 24 is limited by thetop plate 31a of the bracket 31, the engagement with the part 31a doesnot occur until after the desired contact has been established betweenthe members "a and I2. v

If desired, the relay of the present invention 39 concircuit, in whichcase nected in a direct current the shading coils 3| may be eliminated.It is desirable when using the relay to break circuits in whichcomparatively large circuits are passing. and particularly when therelay is being employed with the line conductors II connected in a.direct current circuit, to provide means for ex- 24 and draw itdownwardly current through the ously described,

tinguishing the are which tends to form between the movable contacts andstationary contacts each time the circuit is broken, and for thispurpose the relay may be modified as shown in Fig. 11 to includepermanent magnets in conjunction with the brackets which carry one setof stationary contacts, so that a magnetic ileld is maintained, whichtends to oppose the passage of a gap between separated contacts, thuscausing the flow of current to be shut oii' abruptly when the contactsare separated. In this arrangement, as shown in Fig. 11, themagnetisable core ll corresponds to the core 2! or the constructionpreviously described, and the in sulating plate 83 corresponds to theplate 33 of the first form 01' the invention. All parts of the tworelays are otherwise identical in construction except that the brackets85 oi non-magnetic material, corresponding to the brackets i5 previhavethe contact-carrying portions lle connected by right angularly extendingportions lib with the parts "a which lie in coninner face of theinsulating plate thus mounted closely adjacent the gaps between twostationary contacts and the cooperating movable contact, so that amagnetic field is set up which extends across these gaps or through theregion between the contacts in which the tendency i'or arcing may arisewhen the contacts are separated. The coating oi. varnish on the magingassociated ing panel and said between opposed contacts so that the arcis abruptly extinguished.

Although two forms or the invention have been shown and described by wayof illustration, it will be understood that it may be constructed invarious other embodiments coming within the scope or the appended claim.

I claim: I

A relay construction comprising a core, an insulating panel arranged onone side of said core, means including a plurality of supporting membersattached to said insulating panel and engaging said core for retainingsaid insulating panel in spaced relationship with respect to said core,means including a plurality of studs extending through openings providedin said core and in threaded engagement with said supporting members forsecuring said insulating panel to said core, a supporting panel arrangedon the opposite side of said core, means including additional studsextending through openings provided in said supporting panel and inthreaded engagement with said first-mentioned studs ior supporting saidcore and the parts carried thereby upon said supporting panel, a movablearmature carried by said core, means including a windwith said core forcontrolling the position oi said armature with respect to said core, astationary contact carried by said insulating panel and arranged betweensaid insulatcore, a movable contact arranged between said insulatingpanel and said core and associated with said stationary contact, meansincluding said armature for controlling the position 01' said movablecontact with respect to said stationary contact, and terminals for saidwinding and said contacts carried by said insulating panel.

' OTHO D. GRANDSTAFF.

